"These occurred when the smaller of the two (or more) users fell as a result of the increased energy transferred from the larger bouncer, resulting in a mistimed landing or being projected to an unexpected height or distance," the study said.

The study estimated 20 new trampoline centres opened in the last three years across the nation.

The study's chosen hospital is less than 6km from trampoline park Sky Zone Alexandria and a spokesperson said the park was a member of independent body the Australian Trampoline Parks Australia which released a statement.

We believe that the positives of youth recreational sports far outweigh the negatives.Australian Trampoline Parks Association

"Such studies provide a deeper understanding of safety issues and provide data on our sport allowing us to better educate parents, jumpers and parks so all can fully enjoy indoor trampoline park facilities," the statement said.

"We believe that the positives of youth recreational sports far outweigh the negatives and we are actively engaged in programs aimed at promoting the safety and well-being of jumpers who visit our member parks."